KR100326164B1 - Device for controlling suspension of vehicle - Google Patents

Abstract

PURPOSE: A control apparatus of a suspension for a vehicle is provided to insulate vibration by a hydraulic bush with inserting a link to a vehicle body connection portion of a lower arm, and to improve traveling stability by moving the hydraulic bush with a hydraulic or pneumatic cylinder according to travel state. CONSTITUTION: A suspension control device of a vehicle is composed of a direction control valve regulating and supplying hydraulic pressure according to travel state; an electronic control unit applying a control signal to the direction control valve; a lower arm moving up and down according to hydraulic pressure; a bush(82) connected to the lower arm; a connecting link(833) covering the bush; an assembling member(821) penetrating the connecting link and the bush; a slot part guiding motion of the assembling member; and a cylinder(83) fixed in a bracket(832) and connected to the connecting link. Road holding is improved in turning or traveling at high speed by moving the hydraulic bush.

Description

Vehicle Suspension Control

The present invention relates to a suspension control device for a vehicle that can be provided to move the vehicle body mounting position of the McPherson suspension lower arm (A arm) by a certain distance in the vertical direction to give the driving stability and turning stability when turning at high speed straight running of the vehicle. .

In general, the McPherson suspension control device for vehicles is provided with two fluid chambers in the body mounting portion hydraulic bushing of the lower arm (or A arm) to change the position of the lower body mounting portion of the lower arm by the hydraulic pressure acting on the fluid chamber. The vehicle has a configuration in which the position of the roll center of the vehicle is changed in the vertical direction during the turning and the high speed driving.

As shown in FIG. 1, the conventional suspension control device includes a control unit consisting of a steering angle sensor 520, a vehicle speed sensor 521, and a control device 52, an oil tank 6, and a 4-port three-position directional control valve ( 51), a hydraulic device 5 composed of a hydraulic bush (50).

On the other hand, as shown in Figure 2, the hydraulic bush 50, the elastic body 503 is press-fitted between the inner cylinder 500 and the outer cylinder 501 made of metal, the two fluid chambers ( 504 and 505 are installed, the outer cylinder 501 is connected to the lower arm 4 and the inner cylinder 500 is connected to the vehicle body, respectively.

In the conventional suspension control apparatus for a vehicle configured as described above, when the driving state of the vehicle is input from the sensor and the control unit operates the direction control valve 51, the pressure in one fluid chamber 504 in the hydraulic bush 50 is applied. The opposite fluid chamber 505 is at atmospheric pressure, and a pressure difference occurs between the two fluid chambers 504 and 505.

Accordingly, the fluid chamber 504 to which pressure is applied is expanded and the fluid chamber 505 which is not pressurized is contracted so that the outer cylinder 501 of the hydraulic bush 50, that is, the vehicle body mounting portion of the lower arm 4, is connected to the hydraulic bush ( The inner cylinder 500 of the 50, that is, the position change relative to the vehicle body is generated so that the position of the vehicle body connection portion of the lower arm 4 is changed in the vertical direction.

As such, when the vehicle body side mounting position of the lower arm 4 is changed, the position of the roll center of the vehicle is changed in the up and down direction due to the change in the kinematic characteristics of the suspension device, thereby suppressing roll generation during straight driving and turning of the vehicle. Done.

Nevertheless, a constant pressure is required in the hydraulic bushing 50 when driving a vehicle, but due to the characteristics of the directional control valve 51, it is impossible to maintain an equal pressure in both fluid chambers 504 and 505 in the hydraulic bushing 50. There was this.

In addition, even if an equal pressure is applied to both of the fluid chambers 504 and 505 of the hydraulic bushing 50 from the viewpoint of vibration isolation to prevent the vibration of the wheel, which is the original function of the hydraulic bushing 50, from being transmitted to the vehicle body. When the directional control valve 51 is in the neutral position, both fluid chambers 504 and 505 in the hydraulic bush 50 form a closed flow path while being isolated from the outside. As a result of being sealed in the hydraulic bush, there was a problem in that the characteristics of the hydraulic bush could not be properly set during vibration isolation.

Moreover, the hydraulic bushing 50 mounted on the vehicle body side of the lower arm 4 requires a great lateral stiffness in the vehicle width direction for stability of the vehicle when turning, but in the vertical direction due to the oil pressure of the fluid chamber as described above. In order to generate the displacement, it is necessary to reduce the oil pressure by making the longitudinal stiffness small in the vertical direction. However, there were many difficulties in manufacturing and forming the hydraulic bush so that the longitudinal and lateral stiffness of the hydraulic bush made a great difference.

As described above, the conventional hydraulic system for changing the vehicle body side mounting position of the suspension lower arm using only one 4-port three-position directional control valve 51 has many problems in actual system operation. It has a soft characteristic in the vertical direction and a hard characteristic in the vehicle width direction to satisfy the characteristics of the suspension itself, such as minimizing the change of the wheel wheel alignment caused by excessive deformation of the hydraulic bush during lateral forces such as turning the vehicle. There was a practical difficulty in making a hydraulic bush that could be made.

The present invention is to solve such a conventional problem, the object of the present invention is to secure the vibration isolation function by the hydraulic bushing through the link mechanism on the vehicle body side connection portion of the McPherson suspension lower arm (A arm) while driving conditions By operating a hydraulic or pneumatic cylinder connected to the link in accordance with the hydraulic bush to move a certain distance in the vertical direction of the vehicle body to provide a vehicle suspension control device that can achieve the stability of the vehicle when driving straight, high-speed driving and turning .

1 is a block diagram showing a conventional suspension control device.

2 is a cross-sectional view showing a conventional hydraulic bush.

Figure 3 is a side view showing a suspension control device according to the present invention.

Figure 4 is a front configuration view showing a suspension control device according to the present invention.

5 is a hydraulic circuit diagram of a suspension control device according to the present invention.

* Description of the symbols for the main parts of the drawings *

1: wheel 2: knuckle

3: thrust 4: lower arm

6: oil tank 7: electronic controller

61: strainer 62: hydraulic pump

64: relief valve 65: directional control valve

66: proportional pressure control valve 67: variable orifice

71: vehicle speed sensor 72: steering angle sensor

80: suspension member 83: cylinder

831: ball joint 832: bracket

833: link

In order to achieve the above object, the vehicle suspension control apparatus of the present invention includes a direction control valve for adjusting and supplying hydraulic pressure according to a driving condition of a vehicle, and a control signal calculated by an electric sensor input signal of the vehicle. An electronic controller applied to the vehicle, and a suspension control apparatus for a vehicle provided with a lower arm to move up and down due to the movement of hydraulic pressure under the control of the electronic controller, wherein the bush connected to the lower arm and the bush can be wrapped. A coupling portion provided at an outer side of the coupling link, a coupling member penetrating the coupling link and the bush, and a slot portion elongated in a vertical direction on one side of a suspension member extending from the vehicle body to guide the movement of the coupling member And extending to one side of the suspension member so that the fastening member moves up and down inside the slot part. One end is fixed to the bracket and the other end is provided with a cylinder connected to the connection link.

Hereinafter, with reference to the accompanying drawings will be described a preferred embodiment of the present invention;

The suspension device for a vehicle of the present invention is a configuration in which a link mechanism is provided at a vehicle body side connection portion of an existing McPherson suspension lower arm (A arm), and since the other components except the link mechanism are similar to conventional configurations, the same configuration Elements are described using the same names and same reference numerals.

In general, the suspension control device for a vehicle includes a hydraulic source for supplying hydraulic pressure to the vehicle body side mounting portion of the lower arm, a direction control valve for adjusting the hydraulic pressure generated from the hydraulic source according to the driving situation of the vehicle, and an electrical sensor input of the vehicle. An electronic control device for applying a control signal calculated by the signal to the direction control valve is provided.

3 and 4 are views showing the installation state of the link mechanism according to the present invention from the side and the front. As shown therein, a bush 82 connected to the lower arm 4 is disposed on the side close to the wheel center, and the bush 82 is made to flow up and down by hydraulic and pneumatic pressure outside the bush 82. The link mechanism is installed so that

First, the bush 82 is provided in the shape of a rod, and the outer side of the bush 82 is provided with a connecting link 833 bent to wrap both ends and the upper side of the bush 82, the both ends of the bush 82 A fastening member 821 is installed to penetrate through the bush 82 and the connection link 833.

Next, one side surface of the suspension member 80 extended from the vehicle body is provided with a slot portion 801 which is formed to extend upward and downward to guide the movement of the connection link 833 and the bush 82 upward and downward. The fastening member 821 is inserted.

On the other hand, a ball joint 831 is installed on the upper side of the link link 833, the cylinder rod extending from the cylinder 83 is coupled to the ball joint 831. And the cylinder 83 is fixed to the bracket 832 extending to one side from the suspension member (80).

That is, the cylinder 83 is fixed to the bracket 832 extending from the suspension member 80 connected to the vehicle body, and the connection link 833 through the ball joint 831 to the cylinder rod extending to the lower side of the cylinder 83 ) Is coupled, and the bush 82 is fixed to the inside of the connecting link 833 by the fastening member 821, the lower arm (4) is installed in the bush (82). As a result, the connection link 833, the bush 82, and the fastening member 821 connected to the cylinder 83 are moved up and down by the guide of the slot 801 due to the operation of the cylinder 83.

As shown in FIG. 5, the hydraulic system for operating the cylinder 83 includes an oil tank 6, a hydraulic pump 62, a power source 63 for driving the hydraulic pump 62, and a cylinder 83. Four-port two-position directional control valve 65 for deciding whether to supply or drain pressure to the upper and lower chambers, a flow path is connected to two upper and lower chambers during normal driving, and the hydraulic source and the cylinder 83 upper and lower chambers to control the position of the bush. 4-port 2-position proportional pressure control valve 66 for connecting the flow path of the valve, variable orifice 67 for adjusting the cross-sectional area of the flow path when the two fluid chambers are connected as a flow path, and hydraulic pressure generated from the hydraulic source in the event of system failure. Relief valve 64 that can be relief is included.

The hydraulic system senses the driving state of the vehicle from the vehicle speed sensor 71 and the steering angle sensor 72, and then electrically commands the direction control valve 65, the proportional pressure control valve 66, and the variable orifice 67. It consists of an electronic control device 7 for sending.

The operation of the vehicle suspension control device of the present invention configured as described above will be described with reference to FIG. 5.

1) In normal driving of the vehicle,

Since the control signal is not transmitted from the electronic controller 7 to the proportional pressure control valve 66, the proportional pressure control valve 66 is blocked by the return spring 661, while the flow path between the hydraulic source and the cylinder is blocked. The chambers provided on the upper and lower sides in the 83 are connected to each other through the variable orifice 67.

That is, the two chambers provided in the cylinder 83 are blocked from the outside to form a closed flow path and at the same time therebetween, so that the hydraulic movement is made to the middle of the rough road and the good road driving which will be described later.

2) when driving the rough road of the vehicle,

A large displacement vibration is generated in the wheel and transmitted to the vehicle body through the lower arm 4. In this case, the electronic control device 7 applies a control signal to the channel so as to maximize the cross-sectional area of the variable orifice 67.

As a result, a smooth hydraulic movement occurs between the two chambers provided in the cylinder 83, so that the dynamic damping characteristic can be obtained in the cylinder 83, thereby significantly reducing vibration transmitted to the vehicle body.

3) When driving on a well-paved road

When driving on the pavement, vibration with small displacement is transmitted from the wheel to the vehicle body through the lower arm 4, where the control signal is applied to the electronic control device 7 so that the flow path cross section of the variable orifice 67 is minimized. Done.

As a result, the amount of hydraulic movement between the cylinder 83 chambers is reduced to the extent that the displacement absorbs a small vibration, thereby greatly reducing the noise generated.

4) when turning the vehicle,

By calculating the signals transmitted from the vehicle speed sensor 71 and the steering angle sensor 72, the electronic control device 7 that detects whether the vehicle is turning sends a control signal so that the cross-sectional area of the flow path of the variable orifice 67 is maximized. (83) The control signal is sent to the proportional pressure control valve 66 and the directional control valve 65 to operate the pressure in the lower chamber and the pressure in the upper chamber.

As a result, the bush 82 rises along the slot 801 provided in the suspension member 80 with the piston rod rising, and the roll is determined by the geometric shapes of the lower arm 4 and the thrust 3. By increasing the position of the center of the roll, the roll stiffness increases when the vehicle is turned.

5) good road surface, high speed straight running of the vehicle,

The electronic control device 7 that detects the high speed straight driving state of the vehicle from the vehicle speed sensor 71 and the steering angle sensor 72 has a separate control signal so that the direction control valve 65 is maintained by the return spring 651. The control signals are sent to the variable orifice 67 and the proportional pressure control valve 66 in the state of not sending them to operate them.

That is, the variable orifice 67 sends a control signal to maximize the cross-sectional area of the flow path, and the proportional pressure control valve 66 lowers the pressure of the lower chamber of the cylinder 83 and raises the pressure of the upper chamber, thereby lowering the piston rod. Control signal to send.

Thus, the bush 82 is lowered along the slot 801 of the suspension member 80 to lower the position of the roll center determined by the geometric shape of the lower arm 4 and the thrust 3. It becomes possible.

As a result, the amount of change in the camber or tread of the wheel generated by the unevenness of the road surface at high speed can be significantly reduced, thereby ensuring a straight running stability line.

As described in detail above, the vehicle suspension control apparatus of the present invention,

By using the proportional pressure control valve and the directional control valve to maintain and maintain a constant oil pressure in the upper and lower chambers of the cylinder during normal driving, there is an advantage that the ride comfort and vibration isolation effect is surely performed.

When the control signal is not applied to the proportional pressure control valve, the upper and lower chambers in the cylinder are connected as flow paths to form a closed hydraulic circuit by itself, and the variable orifice is installed in this flow path to adjust the flow path cross-sectional area of the orifice in two stages. It is possible to move the position of the vehicle body mounting portion on the lower arm side up and down to impart turning stability when turning the vehicle and to ensure straightness stability when driving at high speed.

Claims (2)

Directional control valve for adjusting and supplying the hydraulic pressure according to the driving situation of the vehicle, Electronic control device for transmitting the control signal calculated by the electric sensor input signal of the vehicle to the direction control valve, and by the control of the electronic control device In a vehicle suspension control device provided with a lower arm to move up and down due to the movement of the hydraulic pressure, A bush 82 connected to the lower arm 4, a coupling link 833 provided at the outside so as to surround the bush 82, and a coupling passing through the coupling link 833 and the bush 82. The member 821 and the slot portion 801 which are formed to extend in the vertical direction on one side of the suspension member 80 extending from the vehicle body to guide the movement of the fastening member 821, and the slot portion 801 One end is fixed to the bracket 832 extending to one side of the suspension member 80 so that the fastening member 821 is moved up and down in the interior of the other end is connected to the connection link 833, the direction control valve ( Suspension control device for a vehicle, characterized in that a cylinder (83) operated by the (65) is provided. The method of claim 1, Between the direction control valve 65 and the cylinder 83 is connected to the direction control valve 65 and the other side is connected to the upper and lower chambers of the cylinder 83, the proportional pressure of the upper and lower chambers of the cylinder 83 Proportional pressure control valve 66 is provided to adjust the pressure, and the variable orifice 67 is connected to the flow path connecting the upper and lower chambers of the cylinder 83 to adjust the amount of hydraulic movement by adjusting its internal cross-sectional area. Vehicle suspension control device characterized in that.

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